πιθανότητα τρισωμίας

Question

&Kappa;&alpha;&lambda;&eta;&sigma;&pi;έ&rho;&alpha; &sigma;&alpha;&sigmaf;, &theta;έ&lambda;&omega; &nu;&alpha; &rho;&omega;&tau;ή&sigma;&omega; &tau;&omicron; &epsilon;&xi;ή&sigmaf;: &epsilon;ί&mu;&alpha;&iota; 34 &epsilon;&tau;ώ&nu; &kappa;&alpha;&iota; &eta; &alpha;&upsilon;&chi;&epsilon;&nu;&iota;&kappa;ή &delta;&iota;&alpha;&phi;ά&nu;&epsilon;&iota;&alpha; έ&delta;&epsilon;&iota;&xi;&epsilon; &pi;&iota;&theta;&alpha;&nu;ό&tau;&eta;&tau;&alpha; &tau;&rho;&iota;&sigma;&omega;&mu;ί&alpha;&sigmaf; 21, 1 &pi;&rho;ό&sigmaf; 626. (&gamma;&iota;&alpha; &tau;&eta;&nu; &eta;&lambda;&iota;&kappa;ί&alpha; &mu;&omicron;&upsilon; &epsilon;ί&nu;&alpha;&iota; 1 &pi;&rho;ό&sigmaf; 324). &Sigma;&tau;&omicron;&nu; &upsilon;&pi;έ&rho;&eta;&chi;&omicron; &beta;' &epsilon;&pi;&iota;&pi;έ&delta;&omicron;&upsilon; &phi;ά&nu;&eta;&kappa;&alpha;&nu; 2 &kappa;ύ&sigma;&tau;&epsilon;&sigmaf; &sigma;&tau;&omicron; &alpha;&rho;&iota;&sigma;&tau;&epsilon;&rho;ό &kappa;&alpha;&iota; &delta;&epsilon;&xi;ί &chi;&omicron;&rho;&omicron;&epsilon;&iota;&delta;έ&sigmaf; &pi;&lambda;έ&gamma;&mu;&alpha; &delta;&iota;&alpha;&mu;έ&tau;&rho;&omicron;&upsilon; 3mm &kappa;&alpha;&iota; 4.2mm &alpha;&nu;&tau;ί&sigma;&tau;&omicron;&iota;&chi;&alpha;. (&epsilon;ί&pi;&epsilon; &omicron; &gamma;&upsilon;&nu;&alpha;&iota;&kappa;&omicron;&lambda;ό&gamma;&omicron;&sigmaf; &mu;&omicron;&upsilon; ό&tau;&iota; &theta;&alpha; &epsilon;&xi;&alpha;&phi;&alpha;&nu;&iota;&sigma;&tau;&omicron;ύ&nu;). &Omicron;&lambda;&alpha; &tau;&alpha; ά&lambda;&lambda;&alpha; &epsilon;ί&nu;&alpha;&iota; &phi;&upsilon;&sigma;&iota;&omicron;&lambda;&omicron;&gamma;&iota;&kappa;ά, &alpha;&lambda;&lambda;ά &mu;&epsilon;&iota;ώ&theta;&eta;&kappa;&epsilon; &eta; &pi;&iota;&theta;&alpha;&nu;ό&tau;&eta;&tau;&alpha; &tau;&rho;&iota;&sigma;&omega;&mu;ί&alpha;&sigmaf; 21 &sigma;&epsilon; 1 &pi;&rho;ό&sigmaf; 417. &Gamma;&nu;&omega;&rho;ί&zeta;&omega; ό&tau;&iota; &epsilon;&gamma;ώ &pi;&rho;έ&pi;&epsilon;&iota; &nu;&alpha; &pi;ά&rho;&omega; &tau;&eta;&nu; &alpha;&pi;ό&phi;&alpha;&sigma;&eta; &gamma;&iota;&alpha; &alpha;&mu;&nu;&iota;&omicron;&kappa;έ&nu;&tau;&eta;&sigma;&eta;, &alpha;&pi;&lambda;ώ&sigmaf; &theta;&alpha; ή&theta;&epsilon;&lambda;&alpha; &kappa;&alpha;&iota; &mu;&iota;&alpha; &tau;&rho;ί&tau;&eta; &pi;&rho;&omicron;&sigma;έ&gamma;&gamma;&iota;&sigma;&eta;. &Sigma;&alpha;&sigmaf; &epsilon;&upsilon;&chi;&alpha;&rho;&iota;&sigma;&tau;ώ &epsilon;&kappa; &tau;&omega;&nu; &pi;&rho;&omicron;&tau;έ&rho;&omega;&nu;